Kolberg's and Piaget's theories of moral development are mentioned.

According to both Kolberg's and Piaget's theory of moral development, which of the following statements is NOT true?

a) Moral development is rooted in cognative development
b) Appropriate peer interaction promotes moral development
c) Moral development occurs in an invariant equence of stages
d) There may be differences across cultures in the development of moral reasoning especially in the early stages